1. Field of the Invention
This invention relates to a coupling condition detecting device for slide fastener element rows (hereinafter, referred to as element rows), and more specifically, to an element coupling condition detecting device which is capable of detecting whether or not a coupling condition of the element rows of a pair of right and left fastener stringers, which are coupled with each other with a slider inserted therethrough, is acceptable when a continuous slide fastener chain (hereinafter referred to as fastener chain) is carried to various kinds of finish processing portions.
2. Description of the Related Art
Conventionally, a slide fastener finishing apparatus for obtaining a completed slide fastener product to be mounted on trousers, clothes, bag and the like by attaching a slider and stopper onto a fastener chain has been often employed.
Generally, when a completed slide fastener is obtained by attaching a single slider and stopper to the fastener chain, for example, a pair of upper stopper portions are formed separately at an end portion of the fastener chain at first. With the right and left element rows of the fastener chain separate and open, the other separated end portions of the fastener chain are inserted into the slider from its shoulder openings. After the insertion, the respective element rows are sent from an rear opening of the slider with the elements coupled and then a bottom stopper portion for binding the element end portions is provided on the fastener chain. The above-described operation is for attaching the slider and stoppers to the fastener chain which is carried by a gripper device constituted of a pair of right and left components and whose front end is gripped by the gripper device.
As another example of the conventional slide fastener finishing apparatus, Japanese Patent Application Laid-Open No. 2002-306212 previously proposed by the present applicant has disclosed a slide fastener finishing apparatus in which a fastener chain is carried from a slider passing portion disposed on a fastener chain carrying path to an element coupling portion disposed in the downstream of the chain of the slider passing portion. In the slide fastener finishing apparatus disclosed in the publication, a slider is loaded and fixed on the slider passing portion such that the rear opening of the slider is directed to a fastener chain introduction side and thereafter the fastener chain is brought into the rear opening of the slider with right and left element rows of the fastener chain coupled with each other. Then, the element rows, which are separated to the right and left and opened after carried from the shoulder opening of the slider, are inserted into the element coupling portion so as to couple the respective element rows with each other again.
After sent from the element coupling portion, the fastener chain whose element rows are coupled with each other is carried to a stopper portion forming portion for a single stopper, disposed in the downstream of the chain of the element coupling portion. A wire material for the stopper supplied to this stopper forming portion is cut out into a stopper piece of a predetermined length and the stopper piece is bent into a substantially inverted U shape so as to create a single stopper. Then, the stopper is attached to a pair of right and left fastener tapes such that it strides over the element rows of the fastener chain by bending into a substantially lateral C shaped configuration.
It is possible to obtain a slide fastener in which two sliders are contained such that their shoulder openings face each other by using the slide fastener finishing apparatus disclosed in the aforementioned publication. This slide fastener is used at an opening of, for example, a bag, a stationary case and the like and can be opened from its intermediate portion.
To produce such a slide fastener which can be opened from the intermediate portion as seen in the opening of the bag, stationary case and the like, two sliders are loaded on the fastener chain in a condition that their shoulder openings face each other when the two sliders and corresponding stoppers are mounted to the fastener chain. To obtain such a completed slide fastener product, the fastener chain is supplied along the chain carrying path on the slide fastener finishing apparatus in a condition that the fastener chain is gripped by a pair of right and left gripping portions of the gripper device.
The supplied fastener chain is inserted into the rear opening of one slider fixed and supported on the chain carrying path and the fastener chain is sent backward from the shoulder openings of the slider with the right and left element rows open. Subsequently, the fastener chain whose right and left element rows are open is supplied along the carrying path and then inserted into the shoulder openings of the other slider fixed and supported on the carrying path. After the insertion, the fastener chain whose right and left element rows are coupled is sent in a chain carrying direction from the rear opening of the slider. Then, the stopper is formed on the element end portion of the fastener chain whose right and left element rows are coupled.
Usually, when the fastener chain is inserted into the slider, front and back surfaces of the respective fastener tapes of the right and left fastener stringers need to be gripped by the pair of right and left gripper devices and carried horizontally. If the fastener tape is composed of elastic material or thin and soft, a torsion or deflection generated in the slide fastener during its transportation is likely to be applied to the fastener tapes in a separate condition unequally through each gripper device. If the right and left element rows are intended to be inserted into the slider with this condition, a difference in elongation/contraction or a slight difference in length occurs in each fastener tape itself such that a positional deviation occurs in coupling of elements on the right and left element rows or a coupling failure occurs. Thus, it is important to detect whether or not the coupling condition of the elements on the right and left element rows is acceptable when the fastener chain is supplied along the chain carrying path on the slide fastener finishing apparatus.
Generally, in the above-described slide fastener finishing apparatus, a number of finish processing portions are provided in series from the supply side of a continuous fastener chain to its outlet side. When a long continuous fastener chain is carried horizontally along the respective finish processing portions, various kinds of finish processing such as insertion into a slider, mounting of the stopper are carried out. However, because each element in the element rows is a small piece of about a few mm, it is extremely difficult to always check the coupling condition of the element rows accurately with the naked eye during such continuous work for the above-described fastener chain finish processing and further the visual check on a completed product cannot be started until all the processing works are completed. Therefore, in case where the fastener chain is supplied along the chain carrying path on the slide fastener finishing apparatus, there is no other method but checking the coupling condition of the elements of each completed slide fastener product visually after a slider and stopper are mounted on the fastener chain.
However, checking visually the element coupling conditions of the element rows constituted of small pieces of about a few mm in all completed slide fastener products not only takes a great amount of time, but may also affect the health of an operator. Further, that checking work needs a great amount of manppower and labor. Since the checking work is extremely simple and boring, it cannot be continued for a long time and working efficiency is dropped and additionally, there is a limit in mass production with a high accuracy. In views of the above-described circumstances, there has been a great demand for a checking system capable of detecting a positional deviation in the coupling of the elements in the right and left element rows and coupling failure early and efficiently without depending on human labor, thereby leading to improvement of productivity.
The invention has been achieved to solve the above- described conventional problems and a specific object of the invention is to provide a coupling condition detecting device for slide fastener element rows which is capable of detecting a deviation in coupling of a pair of right and left element rows which are coupled with each other with a slider mounted while carrying a continuous slide fastener chain through various kinds of finish processing portions, effectively and securely, thereby reducing finish processing cost and improving product yield.